1. Field of the Invention
The present invention concerns a retainer for an adjustment device of an over-center fastener.
2. Description of the Related Art
Over-center fasteners (also denominated toggle fasteners or latches) are commonly used for securing—and often clamping—two objects together, such as keeping a lid in a closed position on a box or case. A first part of the fastener, referred to as a striker and often having a hook-like shape, is attached to one of the objects. A base member of the other part of the fastener is attached to the other object.
There are two different types of over-center fasteners.
In a first type (see e.g.: http://www.ojop.com/700.htm), a first end of a lever is jointed to the base member so as to be swingable about a first axis. The other end of the lever serves as a handle member. At a distance from the first end, an engagement means is linked to the lever so as to be swingable about a second axis parallel to the first axis. In use, the engagement means is brought into engagement with the first part of the fastener and the handle with the second axis is swung about the first axis to move the engagement means closer to the base member. In order to vary the distance between the second axis and the engagement means, and thereby the engagement force, the engagement means has a threaded stem member engaged in the threads of an internally threaded body member rotatably connected to the lever about the second axis. The body member is normally a cylindrical body rotatable about its axis.
In a second type of over-center fastener (see e.g.: http://www.ojop.com/900.htm), a first end of a link is jointed to the base member so as to be rotatable about a first axis. A second end of the link is jointed to a first end of a handle member. A second end of the handle member is provided with engagement means for engagement with the first part of the fastener. In use, the engagement means is brought into engagement with the first part of the fastener, and the handle member is operated, involving rotation of the second axis about the first one, thereby moving the engagement means closer to the first part. In order to vary the distance between the first and the second axes, the length of the link is variable in that it comprises a threaded stem member engaged in an internally threaded body member connected to the handle and containing the second axis. In this case, the body member is usually formed from folded sheet metal.
In both types of fasteners, there is a desire to prevent undesired relative rotation of the two threaded members. Such rotation often occurs due to vibrations or other exterior influence in the unlocked and unloaded state of an over-center fastener, and may result in that a particular setting of the fastener for a particular clamping case may be lost. This, in turn, may result in that clamping becomes too loose or to tight, or, in case such condition is discovered at all, in a time consuming renewed setting.